DSB cyano?

[CaptPatrick]

Wondering if this is cyano? How can I prevent it from coming back? Don’t mind the glass its getting scraped this evening.

 

[blaxsun]

I know on mine it's mostly coralline and a combination of other goodies, but as I'm apparently not paying my cleanup crew enough to actually clean the edges of the substrate - I don't worry about it.

 

[damsels are not mean]

I don't think it's cyano. The way to remove it would be to cover up that portion of the sand from getting any outside light.